A parsimonious mathematical model of pulse modulated regulation of non-basal testosterone secretion in the male is developed. The model is of third differential order, reflecting the three most significant hormones in the regulation loop, but is yet shown to be capable of sustaining periodic solutions with one or two pulses of gonadotropin-releasing hormone (GnRH) on each period. Lack of stable...

During pregnancy, maternal-endocrine regulation, as well as all their physiology, undergoes profound adaptive changes in the framework of a functional organization structured in three interrelated compartments: the mother, placenta and fetus. Many of these changes are initially induced by estradiol and progesterone produced by the corpus luteum, combined with chorionic gonadotropin. As the preg...

In pregnancy, the decidual cells produce and secrete large amounts of macrophage colony-stimulating factor (M-CSF). M-CSF stimulates the proliferation and differentiation of trophoblasts. In addition, it stimulates them in a dose-dependent manner to produce certain hormones, such as human chorionic gonadotropin and human placental lactogen. Based on these facts, M-CSF is considered to be an ...

Antibodies directed against human follicle-stimulating hormone (FSH) were demonstrated in rabbit serum by neutralization of biological activity. Antibodies that bound FSH-(131)I were produced in rabbits and guinea pigs by repeated injections of FSH. By (131)I immunochemical methods, we found that at least 90% of the FSH-(131)I-binding antibody failed to distinguish the four human glycoprotein h...

Evidence is presented to indicate a generalized role for the terminal sialic acid residues of circulating glycoproteins. Upon injection into rats, all of the desialylated plasma proteins tested, with the exception of transfer& were promptly removed from the circulation and were recovered from the liver. The materials examined included orosomucoid, fetuin, ceruloplasmin, haptoglobin, arz-macrogl...

BACKGROUND Asparagus is a plant with high nutritional, pharmaceutical, and industrial values. OBJECTIVE The present study aimed to evaluate the effect of aqueous extract of asparagus roots on the hypothalamic-pituitary-gonadal axis hormones and oogenesis in female rats. MATERIALS AND METHODS In this experimental study, 40 adult female Wistar rats were divided into five groups, which consist...

Genetic and molecular approaches have enabled the identification of regulatory genes critically involved in determining cell types in the pituitary gland and/or in the hypothalamus. Here we report that Otx1, a homeobox-containing gene of the Otx gene family, is postnatally transcribed and translated in the pituitary gland. Cell culture experiments indicate that Otx1 may activate transcription o...

The critical phylogenetic position of ascidians suggests that evolutionary origins of neuropeptides and hormones of vertebrates are highly likely to be conserved in ascidians, and the cosmopolitan species, Ciona intestinalis, is expected to be an excellent deuterostome invertebrate model for studies on neuropeptides and hormones of vertebrates. Nevertheless, molecular and functional characteriz...

The capacity of pituitary glands to release luteinizing hormone (LH) in response to LHreleasing hormone (LHRH) in vivo may be increased by previous frequent exposures to small quantities of LHRH. This phenomenon, called LHRH self-priming, may play an important role in the control of LH secretion. Our initial objective was to determine whether LHRH selfpriming occurs via a direct effect on bovin...