Long-acting ACTH Research Articles

Plasma Cortisol in the Horse, Diurnal Rhythm and Effects of Exogenous Acth

Peripheral blood plasma Cortisol concentration and its diurnal variation was measured in 4 horses. Mean concentration of Cortisol during 24 hrs. was 42 ng/ml (s ± 20 ng/ml). Peak values occurred at 6 a.m. and the lowest values were observed at about 6 p.m. (mean 65 ng/ml and 20 ng/ml, respectively). Long-acting ACTH at a dose of 150 i.u. was given by intramuscular injection to the 4 horses. Peak Cortisol concentrations markedly exceeding the prestimulation level were obtained between 2 and 4 hrs. after injection. During the immediate 24 hrs. after these peaks, the mean Cortisol level was markedly lower and the cyclic variation out of phase with the basal diurnal pattern. After a gradual adjustment during the second postinjection day, no differences could be seen between the 2 patterns on day 3 after injection.

New Aspects of Androgens, Prolactin, and ACTH Interaction in Men

Some endocrine effects of prolactin (PRL), ACTH, and corticosteroids in testicular function were evaluated by measuring, in normal men, the effects of short-term experimental stimulation and suppression of either plasma PRL levels or adrenal function on plasma androgen profile. PRL levels were increased by administration of metoclopramide or sulpiride or suppressed with bromocryptine. Long-acting testosterone (T) was injected at 8 a.m. on one day in a control period and during a 9-day period of metoclopramide administration. PRL increase was accompanied by a rise in plasma 17-hydroxyprogesterone and T, whereas PRL suppression induced an increase in 5 alpha-dihydrotestosterone (DHT) plasma levels. Peripheral converions of T into DHT and androstenedione, noted after T injection, decreased during concomitant metoclopramide administration. Plasma testicular androgen levels were lowered after long-acting ACTH injections as well as after 24-hr cortisol administration, but the metoclopramide-induced PRL increase appeared to prevent the suppressive effects of ACTH on plasma T. A low-dose dexamethasone treatment did not modify testicular androgen levels. Experimentally induced hyperprolactinemia may have a stimulatory effect on testicular androgen secretion as well as a lowering action on 5 alpha reduction and oxidative T metabolism in man. On the other hand, ACTH-induced androgen suppression seems to be mediated through high circulating levels of corticosteroids; furthermore, PRL and corticosteroids might have reciprocal influences that modulate their effects on testicular function.

Estrogen-like compounds and progesterone in male and female rats before puberty—II: Effects of administration of ACTH, steroidogenesis inhibitors, dexamethasone and hCG

Short-acting ACTH was administered to 14 day old male and female rats, at the time of the plasma peak concentration of those estrogen-like compounds, principally of adrenal origin. Neither plasma concentration nor adrenal content were modified by this treatment while progesterone and cortieosterone productions were stimulated. In contrast, plasma and adrenal concentrations of estrogen-like compounds significantly decreased after the administration of steroidogenesis inhibitors: cycloheximide and aminoglutethimide. After administration of long-acting ACTH, dexamethasone or aminoglutethimide during the 3 day period preceding the peak, the estrogen-like compounds were dramatically decreased in both plasma and adrenals; furthermore, the adrenal content of estrone-like compounds decreased more significantly than that of estradiol-like compounds after ACTH. The pattern of plasma and adrenal steroids on day 15 after a single injection of ACTH on day 7, 9 or 11 was similar to that observed in non-treated rats after weaning. This suggests that ACTH could induce maturation of adrenal steroidogenesis. HCG administration stimulated the gonadal secretions of progesterone and estrogens but did not modify the adrenal production of estrogen-like compounds.

ACTH induced sodium appetite in the rat

Subcutaneous injections of long-acting synthetic ACTH (5 U/day) caused a large increase iin the intakes of both 0.5 M NaCl and water in rats. By the fifth day of treatment the rats were turning over an amount of sodium approximating their own total body sodium. The mineral appetite was specific for NaCl. Intakes of KCl, MgCl 2 and CaCl 2 were unchanged. ACTH was ineffective in adrenalectomized rats suggesting that the appetite was dependent on adrenal hormones.

Induction of cleft palate in hamster fetus following prenatal treatment with ACTH

Hamster fetuses were examined for palatal malformations at term following injections of ACTH, having different durations of activity, during pregnancy. Cleft palates were seen in long-acting ACTH-treated fetuses whose weights were significantly reduced. Morphologically, the cleft involved only the anterior third of the secondary hard palate, suggesting that the long-acting ACTH is a mild teratogen. The hypothesis was thus supported that exogenous administration of ACTH will stimulate the maternal adrenal cortex to produce teratogenic amounts of glucocorticoid and thereby induce cleft palate.

Responses of the immature fowl to a single injection of adrenocorticotrophic hormone

Chicks, aged 1 or 21 d, were injected with long-acting ACTH (6, 12, 30 or 60 IU/kg) and changes in plasma glucose and cholesterol and in adrenal weight and cholesterol measured. 2. No consistent response was observed in the 1-d-old chicks. 3. Hyperglycaemia and adrenal cholesterol depletion could be demonstrated in the 3-week-old bird at all doses. 4. The duration of the hyperglycaemic response was dose-dependent but there was only limited evidence that adrenal cholesterol depletion was similarly dependent. 5. Starving the 3-week-old bird overnight led to a significant hypercholesteraemia which was reduced after ACTH. In contrast no change in plasma cholesterol concentration was noted in fully fed birds.

The Effect of ACTH Administration on Serum Estrogens, LH, and FSH in the Aged

The effect of administration of long acting ACTH on serum levels of estrogens, LH and FSH was studied in aged subjects. Nine women and 5 men between 66 and 90 years of age were examined. One milligram of long-acting synthetic ACTH was given in every 12 h for 2 days. Significant increases in serum estrone and estradiol levels were induced in parallel with serum cortisol at 24 hours and no further change was observed at 48 hours. The estrone/estradiol ratio increased from a control value of 3.0 to 4.0 at 24 hours and to 4.7 at 48 hours (P less than 0.02) compared to control values.

Corticotropic Action of an Intra-Nasally Applied Synthetic ACTH Derivative

The corticotropic action of a synthetic ACTH derivative, D-Ser1 Lys17,18-1-18ACTH, after intranasal insufflation of 1 mg of the peptide was evaluated in 14 normal volunteers. Plasma cortisol and urinary 17-ketogenic steroids and 17-ketosteroids rose significantly over control values in all subjects (P less than 0.001). Plasma cortisol remained above the normal range for comparable clock times for 18 hr, but fell below 15 mug/100 ml after 12 hr. No evidence for suppression of the hypothalamo-pituitary axis was found the day after ACTH administration, as judged by normal plasma and urinary steroid values and normal diurnal variation. Intranasal administration of long-acting ACTH derivatives may provide a simple, painless and effective way to stimulate endogenous corticosteroid secretion.

Effects of acth on steroid C-21 hydroxylation in rat adrenal glands

The activity of 21-hydroxylase in postmitochondrial fractions from normal and ACTH-stimulated rat adrenals has been measured using 11β-hydroxyprogesterone as substrate. Administration of 4 IU/day of long-acting ACTH for 4 days significantly increased basal levels of 21-hydroxylation without effect on NADPH-supported hydroxylation. Acute injection of ACTH, or prolonged administration of the hormone for 14–28 days did not have any effect on basal or NADPH-supported S.A. However, due to the increase in adrenal weight promoted by all the prolonged ACTH treatments, total enzyme activity will be raised in hypertrophic tissue. Adrenals from rats treated with ACTH for 4 days also showed [1] increased hydroxylation of 11β-hydroxyprogesterone after addition of glucose-6-phosphate to the incubations and [2] increased activity of the enzyme glucose-6-phosphate dehydrogenase. These results suggest that the enhanced 21-hydroxylation in 4 day ACTH-stimulated tissue may be the consequence of an activation of the hexose-monophosphate shunt.

Microphallus pygmaeus: Effect of long-acting ACTH preparation on establishment and retention in alimentary canal of the mouse

Outbred albino laboratory mice injected im at 48-hr intervals, over a 22-day period, with 4 iu of a long-acting ACTH preparation and later infected with the metacercariae of Microphallus pygmaeus have a higher worm burden than mice injected with a placebo. Greater numbers of parasites survive in the stomach and later in the duodenum and ileum, the preferred regions of the gut, and the development of the metacercariae into sexually mature forms is also faster in ACTH treated mice.

Clinical Evaluation of Prolonged ACTH and Cortisone Therapy in 114 Cases of Rheumatoid Arthritis: A 3 1/2-year Study

SummaryThe authors report observations made over a 3½-year-period on 114 patients with rheumatoid arthritis who were treated with long-acting ACTH or Cortisone. After prolonged treatment with hormones 30% showed satisfactory improvement (grade I or II). During the same period, however, a total of 208 patients were admitted to the ward under the diagnosis of rheumatoid arthritis. 94 patients did not receive hormone treatment for various reasons. The authors stress that this confirms their previous impression: that a minor percentage only (in casu 16.3%) of all patients with rheumatoid arthritis admitted to a hospital department of internal medicine will finally receive ACTH or Cortisone therapy with a satisfactory improvement.

Circulating Adrenocorticotropin (ACTH) as a Controlled Variable in the Regulation of ACTH Secretion

Rats received 21 daily injections of hydrocortisone acetate, beginning 5 days after bilateral adrenalectomy. Immediately following cessation of hydrocortisone administration, adenohypo-physial adrenocorticotropin (ACTH) concentration was reduced to about 40% of intact, control levels and remained at this low level for 16 days. There followed a gradual increase to intact control levels by 32 days, to 150% of control by 48 days, and to 170% of control by 64 days. The daily administration of a long-acting ACTH preparation following the cessation of hydrocortisone administration altered this response. Adenohypophysial ACTH levels remained lower than in the animals not receiving ACTH, reaching only 50% of control at 32 days and 93% of control at 48 days. At 64 days, ACTH concentration was actually higher in the ACTH-treated group, reaching over 300% of control values. These findings demonstrate (a) that the circulating level of ACTH can, in itself, alter adenohypophysial ACTH concentration, and (b) the importance of timed studies, since, depending on the time chosen, ACTH administration will depress, augment, or indeed produce no change in adenohypophysial ACTH concentration. We conclude that the circulating levels of ACTH can alter ACTH secretion.

ACTH and zinc-phosphate vehicle interact with UCS parameters to influence shuttlebox CAR

The effect of treatment with 10 I.U./kg.bw long-acting ACTH, zinc-phosphate vehicle or physiological saline on the acquisition and extinction of shuttlebox CAR was studied in 160 Wistar male rats. Three UCS intensities were used: 25 VAC, 5.0 mA; 350 VAC, 0.2 mA, and 350 VAC, 0.5 mA. ACTH treatment reduced CAR during acquisition at all footshock intensities. The effect of ACTH upon extinction CAR, however, was a function of UCS intensity during training. At 25 VAC, 5.0 mA ACTH elevated extinction CAR compared to vehicle, but not compared to saline. At 350 VAC, 0.2 mA ACTH treatment elevated extinction CAR over that of vehicle or saline treatments which did not differ; at 350 VAC, 0.5 mA the effects of ACTH and vehicle treatments did not differ, but significantly elevated extinction CAR over that of saline treatment. The results were interpreted in terms of four main theoretical issues: (1) arousal-performance relationships; (2) a possible behavioral action of zinc-phosphate vehicle; (3) the known behavioral effects of elevated levels of plasma corticosteroids; and (4) the possibility of pituitary-adrenal depletion following chronic treatment and stressful testing.

Influence of time factor on the restoration of adrenal weight and cortical functions in hypophysectomized rats.

It has been shown that repeated doses of a long-acting synthetic ACTH preparation (Synacthen Depot®) are able to restore adrenal function in rats with adrenal atrophy (induced by hypophysectomizing the animals and leaving them untreated for varying periods of time). Restoration of responsiveness to single doses of synthetic ACTH (Synacthen®) can be effected after a relatively short time (10 days’ treatment is sufficient for this purpose); restoration of adrenal weight, how ever, calls for at least 30 days’ treatment with the doses used in this study. In other words, the animals’ adrenals, though greatly reduced in size, are nevertheless capable of displaying a virtually normal response to stimulation. This discrepancy indicates that, during the stimulation test, they must be more active than normal adrenals. This phenomenon cannot be accounted for at present.

INFLUENCE OF ANTERIOR PITUITARY ON AVOIDANCE LEARNING AND ESCAPE BEHAVIOR.

Adenohypophysectomized rats were subjected to an avoidance learning procedure. Only 6 of 21 adenohypophysectomized rats achieved the conditioning criterion against 14 of 18 sham-operated controls. The treatment with a long-acting ACTH preparation (ACTH(A1)Zn) during avoidance training resulted in an improvement in the rate of conditioning, which was most optimal following the administration of 1.5 IU. The injection of replacement therapy with cortisone, testosterone, and thyroxine also improved the ability of adenohypophysectomized rats to acquire an avoidance response. The speed with which adenohypophysectomized rats escaped a noxious stimulus in a runway was significantly lower than that of sham-operated controls, indicating that the motor and sensory capacities of this animal were seriously impaired. Administration of ACTH (A1)Zn or of the replacement therapy restored the escape speed toward normal. Accordingly, the deficiency in learning capacity of adenohypophysectomized rats does not seem to depend on the absence of ACTH but on a general debilitation of the adenohypophysectomized organism.

THE ORIGIN OF URINARY DEHYDROEPIANDROSTERONE IN BOARS.

ABSTRACT Dehydroepiandrosterone, generally regarded as a compound formed peripherally from 17-hydroxy-pregnenolone (3β,17-dihydroxy-pregn-5-en-20-one), a steroid present in the adrenal glands, is the most important neutral 17-ketosteroid occurring in the urine of the male domestic swine. However, the excretion of Zimmermann chromogens in boars was not found to increase significantly following the administration of ACTH (2 × 40 IU) and a long-acting ACTH (2 × 50 IU): after the injection of chorionic gonadotrophin (3 × 10 000 IU), the excretion increased in intact boars. In a castrated animal, administration of 3 × 150 IU ACTH and 2 × 120 IU ACTH did not cause an increase in the excretion of Zimmermann chromogens, nor was there any effect after the administration of 3 × 10 000 IU chorionic gonadotrophin. Moreover, the bilaterally castrated animal had a lower basal excretion of Zimmermann chromogens than an intact boar of the same age. The conclusion is reached, that in boars the contribution of the adrenal cortex to the dehydroepiandrosterone excretion is of minor importance. Instead of the adrenal cortex, the testes must be considered as the main source of the precursor of the dehydroepiandrosterone excreted in the urine.

The effect of adrenocorticotrophic hormone on the yield, composition and butterfat properties of cow's milk

SummaryA single injection of 100 i.u. ACTH given to milking cows had no statistically significant effect on the yield or composition of the milk. A long-acting preparation of ACTH, when given to cows in single doses of 200 and 400 i.u., depressed milk yield and raised the butterfat content of the milk. There was no significant change in the SNF content of the milk but the SNF content of the milk serum was increased. Three injections of 300 i.u. of long-acting ACTH given at 24-h intervals reduced yields of milk, fat and SNF and increased the fat and SNF contents of the milk.Small but generally consistent changes occurred in the butterfat characteristics of the milk of all groups treated with ACTH. There was a decrease in the iodine number and refractive index and a rise in the softening point of the fat in all the experiments. The Reichert value of the butterfat was lowered by single or multiple injections of the long-acting preparation. The carotene content of the butterfat was lowered by injections of the long-acting ACTH preparation but the vitamin A content was unaffected.

Bioassay of ACTH Based on the Plasma 11-hydroxycorticoid Concentration in Hypophysectomized Rats

Bioassay of ACTH based on the rat plasma 11-hydroxycorticoid (11-OHCS) was investigated. The method of Silber et al. (1958) in the extraction process and the method of Zenker and Bernstein (1958) in the fluorescent reaction were used for the determination of 11-OHCS in rat plasma, using corticosterone as the standard. The results are summarized as follows : Both the concentration of plasma 11-OHCS (μg/dl) and the relative adrenal weight (mg per 100g body weight) are inversely proportional to the body weight in the intact rat.The plasma 11-OHCS concentration of intact Wistar male rats weighing 100 to 120g is 40 to 50μg per dl, and it decreases to 5 to 8μg per dl 20 hours after adrenalectomy or hypophysectomy.Plasma 11-OHCS concentration in the adrenal venous blood of the hypophysectomized rat is approximately 16pg per dl. It increases immediately after the intravenous injection of ACTH, 10mU per rat, and reaches the maximum level, about 370μg per dl, at 40 to 50 minutes after the injection.The response of plasma 11-OHCS to ACTH is not only more sensitive but greater than that of adrenal ascorbic acid (AAA). In the dose-response regression, a wider dosage-range is obtained with plasma 11-OHCS than with AAA.The data of a 4-point intravenous, assay on an ACTH preparation against the U.S.P. Reference Standard with a total of 28 rats, providing 0.082 for the lambda value of precision index and 84 to 119% for the confidence limit of the calculated relative potency, indicate satisfactory accuracy of the ACTH assay based on plasma 11-OHCS increase.The pattern of plasma 11-OHCS after a single subcutaneous injection of a long-acting ACTH preparation, 1 U.S.P. Unit per rat, does not coincide well with that of AAA. Both responses are produced almost simultaneously, but the restoration of plasma 11-OHCS response is much faster than that of AAA response. When the same ACTH preparation is injected subcutaneously every two hours with a dosage of 1 U.S.P. Unit per injection, the plasma 11-OHCS keeps the maximal level obtained in the case of a single injection, but AAA gradually decreases with the repetition of ACTH injection below the level obtained by the single injection.The merits of rat plasma 11-OHCS as an indicator of ACTH bioassay are discussed.

Plasma corticosterone levels and salt intake in experimental hypertension in the rat

Plasma corticosterone levels were determined in uninephrectomized, adrenalectomized rats during development of corticosterone-induced hypertensive vascular disease. The mean maximum plasma corticosterone concentration (92.6 μg. per 100 ml.) occurred 1 hour after subcutaneous injection of the steroid. This level was not significantly different from that observed (84 μg. per 100 ml.) in normal rats 1 hour after exposure to nonspecific stress. The mean plasma levels of corticosterone in hypertensive rats receiving 2.5 mg. and 1.25 mg. per 100 gm. body weight were 46 and 48.2 μg. per 100 ml., respectively. These values are well within the physiologic range attained during response to stress and only slightly higher than the mean 12 hour levels produced by 8 I.U. of long-acting ACTH. The significant difference observed between the blood pressures of animals receiving 2.5 mg. and 1.25 mg. of corticosterone twice daily is presumed to be due to difference in salt consumption.

THE EFFECT OF PROBENECID AND HYDROCHLOROTHIAZIDE ON THE CLEARANCES OF FREE AND CONJUGATED 17-HYDROXYCORTICOSTEROIDS, TOTAL 17-KETOSTEROIDS, DEHYDROEPIANDROSTERONE AND ANDROSTERONE

The effect of administration of Probenecid and hydrochlorothiazidc on renal clearances of free and conjugated 17-OHCS, total 17-KS, androsteronc (AND) and dehydroepiandrosterone (DEA) has been determined in normal human subjects. The data obtained suggest that the administration of Probenecid causes a sharp fall in the clearance of the 17-KS and mainly of AND, a less marked decrease in the clearance of the conjugated 17-OHCS, and no modification of the clearance of free 17-OHCS. The administration of hydrochlorothiazide in contrast, resulted in a marked increase in the clearance of all steroids measured, particularly AND and conjugated 17-OHCS. In the patients treated with long-acting ACTH and hydrochlorothiazidc, the hormonal clearances, already high at the beginning, as a result of ACTH administration, tended to increase to even a greater extent as compared to the patients receiving hydrochlorothiazide alone, especially in the case of AND. The authors have drawn the conclusion that it is possible to influence the plasma levels of steroids by pharmacological agents acting at the renal level.