Historical perspective of endocrinology. Beginning of science When do scientific explorations begin?...

Historical perspective of endocrinology

Beginning of science

• When do scientific explorations begin?

• Early science– Linked to medicine rather than intellectual

curiosity– Some behaviors/traditions

• No scientific understanding• Scientific merit

History of endocrinology

• Blood drinking and organ eating– Gaining strength– Gaining advantage over enemy– Treatment for diseases (organotherapy)

• Impotence• Endocrine disorders

• What is in the blood?– Source of life (Leviticus 17:11)

Egyptians

• Understanding the role of gonads (ovaries and testis) in sexual reproduction– Fertility and contraception– Removal of ovaries

• No pregnancy

– Removal of testis• Eunuchs serving in Pharaoh’s harem

– Use of tampons as a contraceptive• Materials from male are responsible for pregnancy

Egyptians

• Methods of pregnancy diagnosis– Morning sickness

• Detection of diabetes– Excessive thirst

• Laid the foundation

Greeks

• Hippocrates (father of medicine)– First known physician

• Many clinical Observations

• Considered medicine as science and separated practice from religion

Greeks

• Hippocrates– Theory of inheritance

• Pangenesis theory (Seeds come from all parts of body and stored in testis)

– Theory of four humors• Black bile, yellow bile, phlegm (green), and blood• Correction of health problems through balancing four humors

– Sexing of offspring through testis removal• Right-male• Left-female

– Identification of vascularized glands

Greeks

• Aristotle– History of animals

• Sows– Loss of ovaries via

ovariectomy• Contraception• Increased growth

– Argument against preformation theory

• Embryo dissection– Methods of contraception

• Diet (obesity/starvation)• Rhythm method• Ovariectomy• Vaginal and cervical

environment manipulation

Romans

• Organoectomy and organotherapy– Eating brain for epilepsy– Eating testis for impotence

Romans

• Galen– Discovery of thyroid

gland• Ductless gland similar

to salivary gland

– Vital spirit• Substances from brain

being carried into the blood

– Pituitary gland• Storage of waste

products from brain

Romans

• Galen– Peri Spermatos (on

seed)• Castration

– Decreased libido

– Changed fat deposition

– Changed hair distribution

• Substance from testis affected physical characteristics

Middle ages

• No significant progress in science– Domination of church

• Diseases = act of God• Surgery = dirty medical practice

• Chinese– Cure for Goiter

• Consumption of seeweed and shellfish• Dysfunction of thyroid gland

– Cause of diabetes

• Chinese– Testicular organotherapy– Extraction of steroid and metabolites from

urine• Varying drying temperature to isolate different

steroids

Renaissance (rebirth)

• Explosion of arts and science– Anatomy

• Da Vinci and Michelangelo

– Galileo Galilei– Development of miscroscope and telescope

• Robert Hooke– Discovery of cells

• Antoine van Leeuwenhoek – Discovery of sperms

Renaissance (rebirth)

• William Harvey– Circulation of blood– Refuted preformation theory

• Dissection of uterus immediately after mating– No congealed mass– No female/male parts

• De Bordeaux (vitalist)– Emanation from each organ is crucial for

health• No experiments

Renaissance (rebirth)

• Discovery of iodine as a treatment for Goiter– Bernard Courtois

First endocrinology experiment

First endocrinology experiment

• Hunter and Berthold– Growth of organs during transplantation

• Rooster as a model

• Removal of testis– Removal of male characteristics (comb)

• Transplantation of testis– Normal male characteristics

• Characteristics controlled by substance in blood, not by nerves– Completely disconnected testis

Contemporaries

• Claude Bernard– Exocrine vs. Endocrine gland (liver)

• Bile from gall bladder• Internal secretion (glucose from hepatic glycogen)

• Thomas Addison– Link between adrenal dysfunction and blood

• Addison’s disease (hypoadrenalism)

• Brown-Sequard– Organotherapy

• Extract from testis to rejuvenate older men

• George Murray– Hypothyroid (myxoedematous) patients can

be treated successfully with thyroid extract

• Von Merring and Minkowski– Relationship between diabetes and pancreas

dysfunction• Removal of pancreas resulted in constant urination• Urine from dogs attracted houseflies when their

pancreas were removed

• Hale White– Feeding pancreas/injection of pancreas extract to

treat diabetes• Did not work (allergic reaction/too little insulin being stored in

pancreas)

• Pierre Marie– Pituitary gland tumor as a cause of acromegaly

• Excessive growth hormone from tumor resulted in excessive growth

• Feeding of dried pituitary gland– No effects on growth

• Oliver and Schafer– Relationship between adrenal gland and

blood pressure• Extract from adrenal medulla and pituitary gland

caused increase in blood bressure• Extract from thyroid gland caused fall in blood

pressure

– “On Internal Secretion” (1895)

Discovery of the first hormone

• Starling and Bayliss– Interaction between duodenum loop and pancreas

• Passing of foodstuff (chyme, highly acidic) through duodenal loop stimulated release of enzyme by pancreas

• Initial thought – nervous system (vagus nerve)• Denervated duodenum stimulated release of pancreatic

enzymes when stimulated with acid– Chemical reflex rather than nerve reflex

– Reaction through blood

• Discovery of secretin

What is in the name?

• Hormone– Greek “I excite” or “I arouse”– Transported by blood from one organ, which

secretes the substance, to the organ where the effect is exerted