Rise In Serum FSH Research Articles

Evidence for changes in sensitivity to testosterone negative feedback on gonadotropin release during sexual development in the male rat.

Male rats were castrated at different ages and injected sc once daily for 2 days with either oil or various doses of testosterone propionate (TP). Castration elevated serum gonadotropins at all ages studied from day 15 to clay 88, but the response was maximal for LH at 58 days and minimal at 15 days. The elevation of FSH was minimal at 88 days but similar at other ages. Whereas 10 μg/100 g body wt of TP were sufficient to prevent the rise in serum FSH and LH which occurred 2 days after castration in 15-day-old rats and 10 M-g were still effective in 28-day-old animals, the suppressibility of serum gonadotropins decreased with age and by 58 days the 10 μg/100 g body wt dose was no longer effective. Higher doses of TP suppressed the increase in serum LH and FSH at all ages studied. The results suggest that the sensitivity of the hypothalamic pituitary unit to the negative feedback of testosterone declines during sexual development and that this change, which is especially noticeable at the time of puberty, ...

Effectf of synthetic luteinizing hormone-releasing hormone (LH-RH) in two brothers with hypogonadotropic hypogonadism and anosmia.

Two brothers with hypogonadotropic hypogonadism, cryptorchism and anosmia were given synthetic LH-releasing hormone (LHRH) by a single intravenous injection and serum levels of FSH and LH were measured by radioimmunoassay. A significant rise in both gonadotropins was found after LH-RH; however, this increase did not exceed the baseline normal range. Rapid intravenous administration of LH-RH was repeated after five days of daily intramuscular injections of LH-RH. The rise in serum FSH and LH levels was similar to that of the first test. It is suggested that the minimal response to LHRH was probably not the result only of a chronic deprivation of releasing hormone but at least part of the disorder may involve the hypothalamus as well as the pituitary.

The pituitary-gonadal axis in the female child during infancy and at puberty

Serum FSH and LH (radioimmunoassay), estradio (radioimmunoassay, and testosterone (competitive protein-binding) were studied in 120 healthy females aged 0–20 years, and correlated with physical development. Prepubertal girls (4–9 years) showed low levels of FSH (6–12 μg LER-907%), LH (0.5–2.5 μg%), estradiol (<I ng%) and testosterone (<20 ng%). Puberty (thelarche and pubarche) was accompanied by a rise in all these variables, reaching adult levels by age 14–16. The earliest hormonal change (age 9–11) was a rise in serum FSH, together with estradio and testosterone; serum LH rose later (around age 12). These data resemble our previous findings in male. In 0–2 year old females, serum FSH (8–40 μg%) and LH (1.3–3.0 μg%) levels were higher than those in male infants (FSH 4–10 μg%, p < .01; LH 0.5–2.0 μg%, p < .01). Female FSH and LH levels diminished from age 0–8 years, while in boys these values increased slightly during this time. Estradiol and testosterone levels were not elevated in infancy. Serial determinations of FSH and LH in infant chimpanzees demonstrated similar constant low values (FSH 5–9 μg%, LH 2.2–3.1 μg%) in males; female chimps had higher values (FSH 13–40 μg%, LH 2.2–6.1 μg%). Moreover the females sowed day-to-day cyclicity of varying amplitude (with 6–14 day periodicity). This sex difference in hypothalamo-pituitary function in infancy possibly represents an effect of differing intra-uterine exposure to endogenous androgen. This is the first demonstration of an endocrine sex difference in primates prior to puberty.

Acute effect of castration on serum FSH and LH in the adult woman.

ABSTRACT The sequence of changes in serum FSH and LH levels immediately following surgical or roentgen castration has been measured by differential radioimmunoassays. A prompt and marked rise in serum FSH and LH occurred within a few days after ablation of ovarian function in all subjects, except one who had been pregnant prior to castration and another who had received fluoxymesterone (100 mg/day). Elevation of serum FSH and LH to values equal to or greater than 100 milli-International Units (IRP-HMG) per ml was attained within approximately 20 days after surgical castration and 30–40 days after initiation of roentgen castration. The pattern of increase in FSH release following castration did not differ noticeably from the pattern of increase in LH release. Stilbestrol, in a daily dosage of either 0.1 or 0.2 mg, administered to 3 subjects, had either a slight effect or no effect on these elevated levels of serum FSH and LH post castration. In a dose of 1.0 mg, stilbestrol, administered to one subject, su...