Ovarian sensitivity to exogenous gonadotrophins in phenobarbital treated unilaterally ovariectomized albino rats

Adult cycling female rats were hemispayed and administered with 7.5 mg phenobarbital/100 gm body weight for 15 days. 5IU FSH or FSH+LH per 100 gm body weight was administered from day 13 to 15 to the hemispayed phenobarbital treated rats. Phenobarbital inhibits the ovarian compensatory hypertrophy significantly and increases the cholesterol and lipid levels in the ovary. Administration of FSH alone or in combination with LH restores the ovarian compensatory hypertrophy and decreases cholesterol and lipid levels significantly but LH alone is not much effective. These results suggest that the inhibition of ovarian growth may be due to the lack of availability of pituitary gonadotrophins in phenobarbital treated rats and these actions can be rectified by the administration of exogenous gonadotrophins which indicate that the ovary has not lost its sensitivity due to phenobarbital treatment.

Effect of exogenous gonadotrophins on restoration of ovarian activities in nicotine treated unilaterally ovariectomized albino rats

Adult cycling albino rats were hemispayed and administered nicotine for 15 days. FSH/LH or FSH+LH was then administered to these rats. Nicotine inhibited ovarian compensatory hypertrophy significantly and increased cholesterol and lipid levels in the ovary. Administration of FSH alone or in combination with LH restored the ovarian compensatory hypertrophy and decreased the cholesterol and lipid levels significantly, but LH alone was not effective. The results suggest that the inhibition of ovarian growth in nicotine treated rats may be due to lack of availability of pituitary gonadotrophins and these effects can be rectified by the administration of gonadotrophins.

Kinetics of spermatogenesis in megachiropteran bat, Rousettus leschenaulti (Desmarset): seminiferous epithelial cycle, frequency of stages, spermatogonial renewal and germ cell degeneration

The paper describes in detail the cytomorphology of different types of germ cells, the 10 typical cellular associations or stages of the cycle of seminiferous epithelium (CSE), frequency of appearance of these stages, pattern of spermatogonial stem cell renewal and per cent degeneration of various germ cells in R. leschenaulti. Of the 14 steps of spermiogenesis (stained with PAS-haematoxylin) the first 10 were associated with the stages I-X, whereas, the remaining were found in association with one of the first six stages. The frequency of appearance of the various stages ranged from 3.84% (stage V) to 19.84% (stage I). These observations indicate that stage V is of shortest duration and stage I is of the longest duration in the bat. Five types of spermatogonia (A1, A2, A3, In and B) were identified based on their shape, size and nuclear morphology. Type A spermatogonia are oval with a large nucleus containing 1 or 2 nucleoli. The chromatin showed progressive condensation from A1 to A3 so that the latter appeared darkest among all the A type spermatogonia. The In type derived from A3 are smaller but appear darker than A3 due to heterochromatin crusts along the inner border of the nucleus. The B type spermatogonia derived from In are round and possess single nucleolus. The B type spermatogonia divided mitotically before entering meiosis or the actual production of the primary spermatocytes. The various spermatogonia divided mitotically at fixed stages of the cycle giving rise to their next generations.(ABSTRACT TRUNCATED AT 250 WORDS)

Kinetics of spermatogenesis in the wild squirrel Funambulus palmarum (Linnaeus)

The paper describes in detail the morphology and kinetics of germ cell associations, pattern of mitotic divisions, frequency distribution of different cellular associations (stages) and percent degeneration of various germ cells in the squirrel in which spermatogenesis in adults occurs all year round. Eighteen steps of spermiogenesis were identified based on the development of the acrosomal system using PAS-haematoxylin. These were appropriately divided into Golgi, acrosome, cap and maturation phases. Thirteen types of cellular associations or stages (I-XIII) were characterized along the length of the seminiferous tubule which repeated itself in space and time constituting the seminiferous epithelial cycle (CSE). Of the 18 steps of spermiogenesis, the first 13 were associated with stages I-XIII, respectively, and the rest with the first 9 stages. Spermiation occurred in stage IX. Seven types of spermatogonia [A0, A1, A2, A3, A4, intermediate (In) and B type] were identified based on their shape, size and nuclear morphology. A0 spermatogonia are pale in appearance with homogeneously distributed chromatin surrounded by a thin nuclear membrane. These are present in all stages. A1 are oval in shape and possess a thicker nuclear membrane. They are found in stages VI-X. The chromatin material undergoes progressive condensation from A1 to A4 making the last generation of spermatogonia appear darker. The In spermatogonia which are derived from A4 are morphologically similar to them but smaller in size. The B-type spermatogonia derived from the In types possess a typically round nucleus with uniformly condensed chromatin material underneath the nuclear membrane. The spermatogonia divide mitotically at fixed stages of the CSE giving rise to their next generations. Thus, A-type spermatogonia divide at stages X, XIII/I, IV and V, while In divide at stage VI. During each CSE of the squirrel, 5 peaks of mitosis occur. There is a single generation of B-type spermatogonia. These differentiate into primary spermatocytes and undergo meiosis or maturation divisions which enter to form spermatids. The A4 which divide differentially in stage VI give rise to In- and A1-type spermatogonia. Therefore, A4 spermatogonia form renewing stem cells. Based on the above pattern of spermatogonial mitosis a model for stem cell renewal in the squirrel is proposed. The percentage degeneration of germ cells varied with the cell type. During a single CSE of the squirrel, a total of 42.09% germ cells were found to degenerate. An attempt is made to compare and contrast the kinetics of spermatogenesis in the wild squirrel with that of the other rodents studied so far.