Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Masculinity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources
PubMed2005

Adrenocorticotropic hormone enhances the masculinity of an electric communication signal by modulating the waveform and timing of action potentials within individual cells.

We report here that melanocortin peptides appear to serve as the mechanism by which weakly electric fish couple socially regulated and stress-regulated brain pathways to unique changes in the intrinsic excitability and action potential waveform of excitable membranes in peripheral cells involved in communication. Gymnotiform electric fish modulate their electric organ discharges (EODs) by reshaping the electric discharges of excitable cells in the periphery. These fish show circadian enhancement of the EOD waveform. They also enhance their EOD waveforms within minutes in response to stressors and changes in the social environment, thus altering the communication value of the signal. Changes in the EOD waveform that occur within minutes result from changes in the discharges of individual electrocytes (microEODs) mediated by the cAMP/protein kinase A (PKA) pathway acting on ion channel kinetics. What activates the cAMP/PKA pathway in electrocytes has not been identified. In vivo injections of the melanocortin peptide adrenocorticotropic hormone (ACTH) increase the amplitude and duration of the electric signal waveform of the gymnotiform Brachyhypopomus pinnicaudatus over the course of 1 h. Applied to single electrocytes in vitro, ACTH increases microEOD amplitude and duration within minutes by differentially modulating the action potentials of the two excitable membranes of the electrocyte and changing the timing of these two spikes. Serotonin modulates the EOD in vivo but has no effect on the microEOD in vitro. The cAMP analog 8-bromo-cAMP mimicked the effects of ACTH, whereas inhibition of PKA by protein kinase A inhibitor 14-22 amide blocked the modulatory effects of ACTH, confirming the role of the cAMP/PKA pathway in microEOD modulation by ACTH.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2004

Middle Eastern masculinities in the age of new reproductive technologies: male infertility and stigma in Egypt and Lebanon.

Worldwide, male infertility contributes to more than half of all cases of childlessness; yet, it is a reproductive health problem that is poorly studied and understood. This article examines the problem of male infertility in two Middle Eastern locales, Cairo, Egypt, and Beirut, Lebanon, where men may be at increased risk of male infertility because of environmental and behavioral factors. It is argued that male infertility may be particularly problematic for Middle Eastern men in their pronatalist societies; there, both virility and fertility are typically tied to manhood. Thus, male infertility is a potentially emasculating condition, surrounded by secrecy and stigma. Furthermore, the new reproductive technology called intracytoplasmic sperm injection (ICSI), designed specifically to overcome male infertility, may paradoxically create additional layers of stigma and secrecy, due to the complex moral and marital dilemmas associated with Islamic restrictions on third-party donation of gametes.

Adult↗
PubMed1977

Effect of prostaglandin E2 on masculine sexual behaviour in the rat.

Intracerebral infusion of prostaglandin E2 (PGE2) facilitated copulatory behaviour of long-term castrated rats. Castrated rats were given daily systemic injections of testosterone propionate (50 microgram) or oil vehicle, and then 30 min before behavioural testing they received an intrahypothalamic infusion of either PGE2 or saline. Rats receiving PGE2 in addition to systemic testosterone showed more copulatory behaviour than those receiving PGE2 or testosterone alone.

Animals↗