John C. Finerty

Gonadotrophic cells of the rat hypophysis and their relation to hormone production.

SummaryThe results of these experiments clearly indicate that the PAS-red and PAS-purple gonadotrophs of the rat anterior hypophysis are functionally as well as tinctorially distinct cell types. The PAS-red cells located peripherally in control animals (“peripheral gonadotrophs” of Purves and Griesbach) produce LH. Following castration they begin to appear in greater numbers in the central areas and by 45 days following castration they are predominant in both central and peripheral portions of the glands. At this time after castration the gonadotrophic content of the pituitary gland is predominantly luteinizing in character.The PAS-purple cells which are found in the central portions of control glands (“central gonadotrophs” of Purves and Griesbach) produce FSH. They appear peripherally following castration and are the predominant type of gonadotrophic cell in the glands of short term (10-day) castrates. The gonadotrophic content of such glands is chiefly FSH as shown by bioassay.By 45 days after castration the LH producing “peripheral gonadotrophs” and the FSH producing “central gonadotrophs” have lost their characteristic distribution patterns. Obviously, then, these two gonadotrophic types cannot be accurately followed on the basis of a restricted regional location in the pituitary but must be differentiated on the basis of specific cytological features and staining characteristics.

Tumor Induction in Rats by Single Total-Body X-Irradiation

It is possible to demonstrate in rats the carcinogenic effect of high-dose totalbody X-irradiation. Such neoplasia has been described by Brecher et al. (1) and Finerty et al. (2) after administration of a lethal dose of X-rays to animals protected by parabiosis; by Koletsky and Gustafson (3) with sublethal X-irradiation; and by Maisin et al. (4) with various protective methods during and after X-irradiation. This paper is a report of the lesions obtained in a large series of irradiated rats, with special attention to tumors and to distribution of their site and incidence.

Increased Metabolism in Fat-Deficiency Relation to Dietary Fat.

Summary Disturbance in energy metabolism, as indicated by increased basal oxygen consumption and growth retardation, is prevented when rats receiving a fat-free diet are given daily supplements of methyl linoleate (100 mg) or cottonseed oil (200 mg). However, similar supplementation with a saturated fatty acid (methyl palmitate, 100 mg) in no way modifies the development of the fat-deficiency syndrome.

Response of preputial and adrenal glands of the rat to sex hormones.

Summary and Conclusions The administration of estrogen to intact male rats for 40 days induces hypertrophy of their adrenal glands but has the reverse effect on their preputial glands. The latter effect is undoubtedly a result of the virtual cessation of endogenous androgen production. Alterations in the ascorbic acid content of these glands appear to be a reflection of the marked changes in their weight. Androgen treatment for the same period produces a slight but significant increase in the weight of the adrenal glands and a 2-fold increase in preputial gland weight. This effect on the preputial glands is predominantly a direct one, as it is seen also in hypophysectomized animals. In contrast, no direct action of androgen on the weight of the adrenal glands of hypophysectomized rats was observed. It was found that androgen administration reduces the resting level of ascorbic acid in the adrenal and preputial glands of both intact and hypophysectomized rats. Furthermore, this hormone somehow destroys the responsiveness of the preputial glands to the ascorbic acid-depleting action of a single injection of ACTH.

Endocrine factors affecting weight and ascorbic acid content of rat preputial glands.

Summary 1. The normal level of ascorbic acid in the preputial glands of the young male rat is 60 mg %. 2. Adrenalectomy (3 wks) induces preputial gland hypertrophy, which is partially prevented by DCA. 3. Severe stress produces a depletion of preputial ascorbic acid, which is accentuated in hypothyroid animals. 4. Hypophysectomized rats (24 hr) have a level of preputial ascorbic acid which is 78% that of controls.

Cytological and weight changes in pituitary gland of the severely stressed rat.

Summary Effects of severe stress, immersion in water at 70°C for 5 seconds, were studied on the male albino rat in relation to response of the anterior pituitary. Using 5 different staining methods, no significant changes in percentage of acidophils, basophils or chromophobes were found 1, 3 or 12 hours after stress, although there were marked increases in number of cells per field in the 12 hour post-stress rats. Fresh weight of the pituitary showed no significant change in 1 and 3 hour post-stress animals, but the 12 hour group displayed a marked reduction, which was evident on both an absolute and a relative to body weight basis. Comparison of relative dry weight and amount of fluid lost in drying in unstressed and 12 hour stressed animals revealed that the weight decrease consisted of both fluid loss and reduction in solids.

PROTECTION OF IRRADIATED RATS BY PARABIOSIS WITH ADRENALECTOMIZED OR SPLENECTOMIZED PARTNERS

Numerous investigations have recently been made concerning post-irradiation protection of laboratory animals (1). Miller, et al. (2) effectively combated the lethal effects of irradiation with large doses of Streptomycin. Salisbury and his associates (3) reported some success with exchange transfusion in six dogs. Ellinger (4) reduced lethal effects of x-radiation in mice by administration of desoxycorticosterone acetate (doca) after exposure. Following up a great amount of work on the protective role of the spleen, Jacobson et al. (5, 6) obtained an enhanced survival rate in groups of mice given supralethal dosages of radiation, by transplanting infantile spleens, spleen suspensions, or mouse embryo suspensions, into the peritoneal cavity. Cole, et al. (7) reported good results with single intraperitoneal injections of spleen homogenate. Recovery of irradiated animals has also been increased by bone marrow injections (8). Histopathologic study reveals that, although destruction of hematopoietic tissue wa...

Adrenal ascorbic acid depletion by ACTH in nephrectomized and in subtotally hepatectomized rats.

Summary Neither total nephrectomy nor subtotal hepatectomy have any effect on the moderate decline in adrenal ascorbic acid which results from the intravenous injection of 0.5 μg/100 g ACTH. It is concluded that ACTH is not preferentially inactivated or withdrawn from the circulation by either liver or kidneys.

Hematologic Changes in Rats Protected from Lethal X-Radiation by Post-Irradiation Parabiosis

Since its introduction by Brecher and Cronkite (1), post-irradiation parabiosis has served as a satisfactory means of protection of experimental animals from lethal amounts of X-radiation. The mechanism of this protection has remained obscure, however. The state of parabiosis is characterized by a relatively large exchange of blood between the two partners (2), and it is thought that this exchange may transmit the protective factors. The importance of the hemapoietic system in protection from irradiation damage has been indicated by other methods, such as spleen or bone marrow shielding (3, 4) or injection of spleen or bone marrow homogenates (5, 6). Previous pre-irradiation parabiosis studies have demonstrated exchange of leucocytes and erythrocytes and have shown that the damage to the parabiont is not as severe as that of the single animal, presumably owing to the cross circulation (7, 8). It is the purpose of the present experiment to investigate the hematologic aspects of post-irradiation parabiosis, i.e., surgical union after X-radiation, in an attempt to elucidate the role of circulating blood in protection from radiation injury.