Oxytocin in Mammals Alex Trei Danny Z Zach C Abbey E

Gland The Pituitary Gland is responsible for the excretion of the Oxytocin hormone in mammals. It is also present in the hypothalamus.

Lipid-based/Peptide-based Oxytocin is a peptide-based hormone

Pathway/Mechanism Oxytocin follows the mechanism pathways of parturation and lactation. It also plays a role in the labor process in females. Oxytocin does use secondary messengers in its pathway. Since it is peptide based it is transduction.

Cellular Response The cellular Response to Oxytocin is that it causes the stimulation of milk ejection, stimulation of uterine smooth muscle contraction at birth, and the establishment of maternal behavior. It does not change the cell but it activates the G protein which causes actions like contractions in the uterus and breast feeding.

Positive or negative feedback? Childbirth is an example of a positive feedback mechanism. Whereas a negative feedback mechanism will serve to reduce or negate the original stimuli, a positive feedback mechanism will enhance and reinforce the original stimuli. In the case of childbirth, the initial stretching of the cervix causes local stretch receptors to send nerve impulses (afferent pathway) to the hypothalamus (control center), which will cause the pituitary gland to secrete oxytocin into the blood stream (efferent pathway). The oxytocin causes the uterus to contract resulting in further stimulation of the stretch receptors.

Alterations that affect the pathway In women who go into preterm labor, relcovaptan (which is a nonpeptide vasopressin V1a receptor antagonist) was reported to inhibit uterine contractions. In a study in 18 women in preterm labor between 32–36 weeks, 12 patients received at random a single oral dose of relcovaptan and 6 patients received placebo, while uterine contractions, were monitored up to 6 h after administration. Relcovaptan inhibited uterine contractions, and, compared with placebo, the difference was statistically significant.

Relcovaptan relcovaptan