B.R. Maiti

Histological and functional changes of oviductal endometrium during seasonal reproductive cycle of the soft‐shelled turtle, Lissemys punctata punctata

Scanning electron and light microscopic studies reveal significant changes in the endometrial histophysiology of the soft‐shelled turtle Lissemys punctata punctata during its seasonal reproductive cycle. Scanning electron microscopy shows the entire oviductal mucosa to be only slightly folded throughout the non‐breeding period (regressive, quiescent, preparatory and recrudescent phases). With the onset of the breeding phase, the mucosa shows extensive foldings and convolutions. The adluminal mucosal lining of the non‐breeding oviduct is covered by a tall, dense ciliary bed, interrupted by a few fissures and pits. Microvilli‐bordered secretory cells only appear amongst the ciliated cells during the breeding phase.

Influence of prolactin on mitotic activity of the bursa of Fabricius of the chick.

The effect of ovine prolactin (NIH-LTH) in different does (1.5, 5.0, 10.0 IU) on the mitotic activity of the bursa of Fabricius of the chick was studied. Prolactin at all doses increased the mitotic activity, but the lowest dosage (1.5 IU) was most effective). Also, prolactin, at all doses, inhibited histologically bursal secretory activity. Thus, dual action of prolactin on bursal activity in chicks is indicated.

Circadian rhythm in blood sugar and adrenomedullary hormonal concentrations in an avian and a reptilian species

The aim of the present investigation was to ascertain the circadian rhythm in the concentration of blood glucose and adrenal medullary hormones in the parakeet and the turtle. These substances were measured four times (0600, 1200, 1800, and 2400 hr) over a 24-hr period. The concentration of blood glucose and adrenal adrenaline and noradrenaline was higher during the day (0600 through 1800 hr) than that noted at night (2400 hr). The pattern of fluctuation was almost similar in both the animal species. The finding suggests that there is a clear circadian rhythm in the concentration of these substances in the parakeet and the turtle, and that this may be due to fluctuation in the activity of the animals.

PHOTOTHERMAL EFFECTS ON OVARIAN GROWTH AND FUNCTION IN THE SOFT-SHELLED TURTLE LISSEMYS PUNCTATA PUNCTATA

Investigations were carried out to find out the role of higher and lower ambient temperatures together with short and long photoperiods on ovarian growth and secretion of steroids (estradiol-17 beta and progesterone) in the adult female soft-shelled turtle Lissemys punctata punctata during the preparatory, recrudescent, and quiescent phases of its seasonal reproductive cycle. In each phase, females were treated with 3 degrees C higher and 3 degrees C lower than the mean highest and lowest ambient temperatures in association with short and long photoperiods for short-term (4 week) and long-term (8 weeks or more) durations. Short-term high-temperature treatment significantly stimulated ovarian growth and secretion of estradiol-17 beta during the preparatory phase. Eight-week treatment failed to exercise further stimulation over 4-week treatment, whereas 10-week treatment caused regressive changes of ovary (atresia of follicles). Both short- and long-term high-temperature treatments caused degeneration of ovarian follicles during the recrudescent phase. Low-temperature treatment slowed down ovarian growth and secretion in both the preparatory and recrudescent phases. In the quiescent phase, low- as well as high-temperature treatments exercised little influence over the refractory ovarian growth and secretion. Photoperiod appeared to have no effect on female reproduction in any phase. Thus, high temperature is suggested to have a triggering role on ovarian growth and secretion of estrogen at the early preparatory phase, but once the ovarian function sets in, high temperature seems to have a regressive rather than stimulatory effect on ovarian growth and function.

Study of atresia in the ovary during the annual reproductive cycle and nesting cycle of the pied myna

Atretic follicles of the ovary of the Indian pied myna (Sturnus contra contra) were studied in birds collected each month throughout the year. Histological examination included histochemical techniques for 3β‐hydroxy‐steroid dehydrogenase (3β‐HSDH) and for lipids. Atretic follicles were mainly of two types: nonbursting (lipoidal and cystic) and bursting (Types I–VI). Nonbursting atresia was observed in the smaller follicles (< 500 μm in diameter), whereas larger follicles (> 500 μm in diameter, viz., small developing, large developing, and yolky follicles) showed exclusively a bursting type of atresia. Sudanophilic lipid was found in both types (lipoidal and cystic) of nonbursting atresia, but was present only in early stages of bursting atresia. Activity of 3β‐HSDH was absent in nonbursting atresia, but present in early stage of bursting atresia. Nonbursting atresia was common throughout the year and higher in frequency than the bursting type. Bursting atresia was common during March through May and attained its peak level during the nesting cycle.

Gonadal hormone-dependent changes in the concentrations of sialic acid and fructose in the seminal glomus and of glycogen in the oviduct of the Indian pied myna

Sialic acid and fructose contents of the seminal glomus and glycogen content of the oviduct were estimated in the normal, gonadectomized, and gonadectomized plus sex steroid (testosterone in male and estradiol in female birds)-treated Indian pied myra, Sturnus contra contra. The levels of these substances declined on the sixth day after gonadectomy; sex steroid administration increased the level of these substances in gonadectomized birds. The findings indicate that the concentration of these substances in the accessory reproductive organs in the Indian pied myna are influenced by the respective gonadal hormones.

Scanning electron microscopic study of the male genital tract during its highest and lowest activities in the seasonal reproductive cycle of the soft-shelled turtle

The objective of the present investigation was to study by scanning electron microscopy the epithelial surface structures of different segments of the male genital tract (ductuli efferentes, proximal and distal epididymes, and vas deferens) during highest (July) and lowest (January) activity in the annual reproductive cycle of the soft‐shelled turtle. The study has revealed that there are distinct regional differences in the male genital tract. The ductuli efferentes have three types of cells, long‐ciliated, short‐ciliated, and microvilli‐bordered cells. The proximal epididymis has two types of cells, microvilli‐bordered cells and smooth‐surfaced cells; the distal epididymis has only tall, smooth‐surfaced cells. The vas deferens contains both smooth‐surfaced and microvilli‐bordered cells. Cells of the genital tract in July show several differences from comparable cells in January: Ciliated cells of the ductuli efferentes have longer cilia, cells of the proximal epididymis have microvilli distended by secretory materials, and cell apices in the distal epididymis are surmounted by an abundance of huge secretory blebs. There is no discernible change in the vas deferens. The findings suggest that all segments of the male genital tract, except the vas deferens, become active in July and have regressed by January in the annual sexual cycle.