Non-pregnant Luteal Phase Research Articles

Serum and urinary hormones during pregnancy and the peri‐ and postpartum period in an Asian elephant (Elephas, maximus)

AbstractBlood and urine samples were collected weekly from an Asian elephant (Elephas maximus) for 10 months before conception, throughout pregnancy, and for 10 months after parturition. Additional daily samples were collected for 41 days before through 10 days after parturition to define endocrine events during the peripartum period. During gestation, serum progesterone concentrations increased gradually and, after ∼13 weeks, were higher (P < 0.05) than those observed during the nonpregnant luteal phase. Concentrations peaked at ∼12 months of gestation, gradually declined during the last month, and then decreased sharply to nondetectable levels 2 days before parturition. A 12 week lactational anestrus was observed before cyclicity resumed. The urinary profile of progestagen excretion paralleled that of circulating progesterone (r = 0.79; P < 0.05); however, radioimmunoassay of HPLC‐separated fractions of urinary eluates indicated that this immunoactivity was not associated with native progesterone. After remaining basal through the first 16 weeks of gestation, serum prolactin concentrations increased to 100‐fold about midterm and remained elevated until after parturition. Neither serum nor urinary cortisol concentrations were altered during pregnancy, but both increased markedly the day after parturition and remained elevated above prepartum levels for several weeks thereafter. These data indicate that analysis of serum prolactin can confirm pregnancy in the Asian elephant after ∼4 months of gestation and that daily monitoring of serum or urinary progestagens is useful for predicting parturition. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.

Histological observations of canine cystic endometrial hyperplasia induced by intrauterine scratching.

Of eight mongrel bitches, the antimesometrial side of the nonpregnant left horn of the uterus at the pregnant or nonpregnant luteal phase was scratched with a Kirschner's wire. Cystic endometrial hyperplasia (CEH) was induced in seven of the eight bitches (87.5%). No difference in the incidence of CEH in the left horn was seen between the pregnant and the nonpregnant groups. Histological examinations showed CEH with a dilatation of the basal glands, resembling "Swiss cheese endometrium".

Plasma androgens during early pregnancy in the baboon (Papio cynocephalus)

Time-mated baboons (n = 8) were bled throughout the luteal phase of the cycle of conception, and an equal number of nonpregnant animals were studied as controls. A significant increase in plasma testosterone and androstenedione was seen in the cycle of conception prior to expected menses, whereas the levels in nonpregnant baboons were unchanged throughout the luteal phase. Plasma testosterone and androstenedione continued their rise in three pregnant baboons sampled between days 16 and 33 of gestation. In an additional three baboons bled at 4-day intervals from day 35 through day 75, there was a further increase to about day 40, but by day 50 the androgen levels had declined to nonpregnant luteal phase levels and remained constant. Treatment with human chorionic gonadotropin during the nonpregnant luteal phase caused increases in both testosterone and androstenedione. Removal of the ovary bearing the corpus luteum at day 20 of gestation resulted in abortion and a sharp drop in plasma progesterone and estradiol. One baboon had a dramatic decline of the elevated plasma androgen following oophorectomy, while another that did not have elevated androgen levels showed only a trivial decline. Pregnancy continued in two baboons in which the corpus luteum-bearing ovary was removed at day 25 or day 30. There was only a slight drop in plasma progesterone postoperatively and a rapid return to normal levels. A similar decline, with a more gradual recovery, was noted in plasma estradiol and androgen levels. In one animal the androgen levels were increased by about day 40 and subsequently declined by day 50, just as did the androgens of unoperated pregnant baboons. Estrogen administration in early pregnancy causes a suppression of the normal increases in plasma estradiol and androgen levels.