What is adiponectin??

What is ADIPONECTIN. ?ADIPONECTIN.  This is a polypeptide secreted from adipose cells. It influences glucose regulation and fatty acid metabolism In obese men and women this level is low (inverse correlation.).ACTION: to promote loss of wt. complementing the action of leptin in the brain Adiponectin as well its receptors are more to undergo mutations à may promote obesity which is not controlled by dieting and exercise. Such genetic disorders are noticed in cases with Met syn ad DM(see Ref: www.clinicalgynendoandinfertility.com).

What is  LEPTIN??.

Leptin: Derived from Greek word LEPTOS- 167 AA peptide secreted like Adiponectin from adipose tissues of body. There is family proteins with which are bound in blood stream.Mode of Action: on CNS- an energy balance-expenditure and eating behavior.

What does  LEP GENE do ??

In humans the Ob gene of mouse is designated as LEP gene. Located at Chr. 7.(Chr 7q31.3. )  . In mice there are several mutations of Ob gene-resulting into decrease formation of an enzyme called carboxypeptidase which helps in conversion of prohomone (proinsulin) to insulin. Mutation can also affect insulin receptor.

 The Leptin Receptor Family

The Leptin Receptor Family:- belongs to cytokine receptor family. These acts by proteins that phosphorylates the  receptor after binding  . There are multiple isoform of -the long form-which is class I cytokine Receptor family. This receptor acts by proteins that phosphorylated the receptor after binding and STAT Proteins that are activated after phosphorylation. -->     à Activated STAT proteins after phosphorylationà migrate to nucleus   à stimulate gene transcription inside the cell concerned. The long form-receptor works through STAT proteins. But gene knock outs specific for STAT proteins are not obese. Indicating there are other pathways /other signaling pathways activated by leptin. Db gene encodes the leptin receptor. Te Db mutation converts the long form to the inactive short form à Leptin resistance  à obesity.

Ob GENE.

In 1944 Ob gene was identified the gene responsible for obesity in mouse.(Speroff-pp. 865-8^th ed.).In rodents this gene located in Chromosome 6, but in humans this is located in Chr. 7. There can be also mutation of leptin receptor genes located in human chr. 1

HUNGER, APPETITE   CENTE   IN   HYPOTHALAMUS.

The appetite centre is located at ventro-medial nucleus of hypothalamus. Appetite and hunger are centers are located here but these are controlled by variety of neurotransmitters and peptides, hormones Tumours, trauma, aneurysms, Inflamm can cause hyperphagia.

Afferent signals are from peripheral tissues, opiates, Substance P, Cholecystokinin , taste buds all promote and stimulate appetite centre.The following substances inhibit appetite: - CRH (Corticotrophin releasing hormone/ factor), Neurotensin, oxytocin, Cyclo(HisPro)- a peptide derived from TRF(TRF/H).