What does leptin do in mice?

What does leptin do in mice?

The ob gene protein product, leptin, is an adipocyte-derived circulating protein. Administration of recombinant leptin reduces food intake and increases energy expenditure in ob/ob mice, suggesting that it signals to the brain the magnitude of fat stores.

Do mice have leptin?

In humans, leptin levels in obese T2DM patients are typically ~10 ng/ml, compared with ~5 ng/ml in non-diabetic obese subjects [169, 170]. The serum leptin level of db/db mice is much higher and quite variable, ranging from ~100 ng/ml in 4-week-old mice [171] to ~4000 ng/ml in 6-week-old mice [172].

Do db db mice produce leptin?

The db/db mice (and the fa/fa rat) have normal to elevated levels of leptin but are resistant to its effects, thus producing a phenotype very similar to the ob/ob mouse.

How does leptin affect obesity in mice?

In lean mice, leptin has minimal effects on food intake, but causes the loss of body fat, presumably due to a leptin-induced increase in energy expenditure (19).

What tissues respond to leptin in mice?

Tissue distribution of mRNA The leptin gene is strongly expressed in white adipose tissues (WAT) and also in mammary epithelial cells and bone marrow. In mice, the leptin gene is expressed in the WAT, liver, and pituitary gland. In the rat, leptin mRNA is distributed in the stomach, muscle, and pituitary gland.

What was the effect of leptin injections on mice that were leptin deficient due to a defective gene?

Recessive mutations in the ob gene lead to defective production of leptin, with the ob/ob mouse becoming obese, insulin resistant, and infertile from early life. Intraperitoneal injections of leptin into ob/ob mice result in a fall in body weight within days and by 33 days 40% of the original weight is lost.

Why do rats with mutations to the ob gene become obese?

Models of type 2 diabetes The ob/ob mouse has a mutation in the leptin gene resulting in leptin deficiency, and, as a result of this mutation, the ob/ob mice have increased appetites and develop severe obesity.

What is the difference between ob ob and db db mice?

Ob/ob mice are characterized by a mutation of the obese (ob) gene encoding leptin, whereas the db/db mice have a mutation of the diabetes (db) gene encoding for the ObR [20].

What does db db mice mean?

Definition. The db/db mouse is a genetically mutated mouse in which leptin receptors do not function properly. The db / db mouse is extremely obese and has many of the metabolic defects (hyperphagia, hyperglycemia, hyperinsulinemia, and infertility) found in ob/ob mouse.

Why is leptin high in obesity?

Obese people have unusually high levels of leptin. This is because in some obese people, the brain does not respond to leptin, so they keep eating despite adequate (or excessive) fat stores, a concept known as ‘leptin resistance’. This causes the fat cells to produce even more leptin.

What was the effect of leptin injections on mice that were leptin deficiency due to a defective gene?

What tissues produce leptin and the leptin receptor proteins?

Leptin is the protein product encoded by the obese (ob) gene. It is a circulating hormone produced primarily by the adipose tissue.

What is the function of leptin in the ob/ob mouse?

One role of leptin is to regulate appetite by signalling to the brain that the animal has had enough to eat. Since the ob/ob mouse cannot produce leptin, its food intake is uncontrolled by this mechanism.

What is the ob/ob mouse?

The ob/ob or obese mouse is a mutant mouse that eats excessively due to mutations in the gene responsible for the production of leptin and becomes profoundly obese. It is an animal model of type II diabetes. Identification of the gene mutated in ob led to the discovery of the hormone leptin, which is important in the control of appetite.

Do leptin deficient mice develop hyperglycemia?

Leptin receptor-deficient db/db mice develop hyperglycemia by 2 months of age, but not all db/db mice develop it [69]. In db/db mice at 10 weeks of age, fasting blood glucose levels can reach ~600 mg/dl in comparison to ~150 mg/dl in control mice [70].

What is the normal range of leptin in obese patients?

In humans, leptin levels in obese T2DM patients are typically ~10 ng/ml, compared with ~5 ng/ml in non-diabetic obese subjects [ 169, 170 ]. The serum leptin level of db/db mice is much higher and quite variable, ranging from ~100 ng/ml in 4-week-old mice [ 171] to ~4000 ng/ml in 6-week-old mice [ 172 ].